1. Field of the Invention
The present invention relates to an electronic apparatus including a high frequency noise source and a fan ventilation hole for controlling temperature, and in particular, to a configuration preferable for providing measures against radiation of high frequency noises.
2. Description of the Background Art
In recent years, video performance and audio performance of digital AV apparatuses have become substantially superior to those of analog apparatuses. Meanwhile, from a designing point of view, it is necessary to take measures against radiation of high frequency noises (electromagnetic waves) which are generated due to a high operating frequency of a digital processing circuit and data communications, and measures against heat generated from the digital processing circuit (e.g., LSI).
However, the two kinds of measures conflict with each other. In other words, it is preferable that the opening area of a fan ventilation hole for releasing heat is as large as possible in order to improve ventilation efficiency, and at the same time, is as small as possible in order to suppress the radiation of high frequency noises. Japanese Patent Laid-open Publication No. 5-259689 discloses a magnetic-shielding housing in which a magnetic-shielding board is disposed near a fan.
As described above, for an electronic apparatus, the measures against heat and the measures against radiation conflict with each other. In order to release the heat generated in the electronic apparatus, it is necessary to improve the ventilation efficiency. Therefore, it is preferable that the opening area of the fan ventilation hole is as large as possible. On the other hand, in order to suppress the radiation of high frequency noises generated in the electronic apparatus (radiation from the inside to the outside of the electronic apparatus), it is preferable that the opening area is as small as possible.